Amplified stethoscope



April 22, 1947. M. F. THIBOS AMPLIFIED' STETHOSCOPE Filed Oct. 28. 1944 2 Sheets-Sheet l 5 Am o 4 OOO INVENTOR. Mew/e F. Tfi/fi 00 @Lb A 7 TORNEKS.

April 22, 1947.

F. THIBQS 2,419,471

AMPLIFIED STETHOSCOPE Filed Oct. 28, 1944 2 Sheets-Sheet 2 fi v.

\ INVENTOR.

Mew/e f. 7/7z'baa ATTORNEXJ'.

Patented Apr. 22, 1947 UNITED STATES PATENT OFFICE AMPLIFIED STETHOSCOPE Merle F. Thibos, Niles, Mich. Application October 28, 1944, Serial No. 560,762

11 Claims.

This invention relates to improvements in amplified stethoscopes.

The main objects of this invention are:

First, to provide a stethoscope which embodies therein sound amplifying means generally of conventional form whereby the sounds created by the heart or other organs of the body are picked up by a microphone, converted into electrical impulses, amplified by the tubes in the amplifier, and converted into sound by a sound reproducer.

Second, to provide an amplified stethoscope that may be used in a manner similar to that of the conventional stethoscope to which every physician is accustomed.

Third, to provide an amplified stethoscope that maybe used under any and all conditions where a stethoscope is needed. Fourth, to provide an amplified stethoscope in which all the parts thereof as a unit may be easily slipped into a coat pocket or may be easili suspended from around the neck when moving from room to room, or may be carried as a single unit in any other convenient position.

Objects relating to details and economies of the invention will appear from the description to follow. The invention is defined and pointed out in the claims. A preferred embodiment of the invention is illustrated in the accompanying drawing, in which:

Fig. 1 is a side elevation of the stethoscope, showing a housing for containing the microphone, amplifier, batteries, and sound reproducer, and connections from the sound reproducer within the housing to the ear pieces.

Fig. 2 is a section of the housing, taken on line 2-2-of Fig. 3, and also illustrates in plan the relative arrangement of the parts within the housing.

Fig. 3 is a section of the housing, taken on line 3--6 of Fig. 2, and also illustrates in plan the relative arrangement of the parts within the housin viewed at right angle to the position shown in Fig. 2.

Fig. 4 is an end view of the housing illustrating the microphone disposed in said end.

' Fig. 5 is a fragmentary side-elevation of the housing, showing push button controls for the amplifier, projecting from the housing. Fig. 6 is an enlarged fragmentary detail sectional view on the line 6-45 of Fig. 2.

Fig. 7 shows a wiring system for the tubes of the amplifier, generally of a conventional form.

Referring to the drawing, the reference numeral I designates a housing for a microphone, sound reproducer, amplifier, and batteries, supported by a chassis 2 within the housing. The housing l is of elongated formation and has an opening 3 at one end thereof through which the microphone 4 projects to permit the same to be placed against the body of the patient. The other end of the housing is of a size and shape to constitute a handle 5 to be grasped by one hand of the physician for positioning the microphone 4 against the body of the patient to pick up the sounds of the heart or other organ of the body. To provide ready access to the tubes, batteries and other parts, the handle portion 5 of the housing l is removably mounted on the chassis 2 and is adapted to he slipped longitudinally from over an end portion of the chassis, by removing the retaining nut 6 from the end of the bolt 1 which projects through an opening in the end of the, handle and also through an opening in the bar 8 soldered or otherwise secured to the end of the chassis, the bar 8 retaining the head of the bolt between the same and the end portion of th chassis, as shown in Fig. 2.

One portion of the chassis 2, constituting a partition member 9, extends longitudinally of the handle 5 substantially midway between the opposite sides there0f.. On one side of this partition member 9 are supported the tubes l0, condensers, coils and other parts of conventional design, while on the other side is supportedthe B battery vll between the springs l2, l3, with the spring l2 grounding one terminal of the battery to the metal chassis. 2 and with the other spring l3 insulated from the chassis and connecting the other'terminal of the battery II to the wiring 14 leading to the plates of the tubes, as shown in Figs. 2 and 7. The chassis 2 is also provided with a compartment 15 for receivingthe A battery [6. Projecting transversely of the openings at the opposite ends of this compartment are springs l1 and I8, with the spring I! engaging the bottom of the battery and grounding it to the chassis, and with the spring 18 insulated from the chassis and engaging the terminal at the top or opposite end of the battery and connectingthebattery to the filament circuit of the tubes through the connections hereafter described.

A-switch I9 is used to reduce the volume by the introduction of negative feed-back in the amplifier. Switch l9, as shown in Figs. 2 and 7, comprises two metal plates 26 and 2! disposed transversely of each other and both having insulated support on a wall of the compartment I5 of the chassis 2, with the plate 20 wired to the plate of one of the tubes and the other plate 2| wired in series with resistorZ'l to a grid of a tube Ill, and composed rear ofthemicrophone 5.

3 of resilient metal and having one end fixedly secured to its support and the other end normally slightly spaced from the plate 20.

To close the volume reducing circuit, the free end of the spring 2| is forced into electrical contact with the plate 20 by mean of a push button 22 of insulated material and projecting from the interior of the handle to the exterior thereof to be engaged by a finger of the operator. The

push button 22 is provided with an annular rib 23 abutting on one side thereof the interior surface of the handle 5 and on the opposite side thereof one end of a coil spring 24 encircling the push button. The spring 24 is under compression between the rib 23 and a metal plate 25 through an opening in which the button 22.

passes. The intermediate portion of this plate is spaced from the interior of the handle and its opposite ends are secured thereto by screws 26 with their inner ends threaded into said plate and with their heads engaging the exterior of the handle: Only-one switch l'9-is-shown--in Fig. 2" but obviously there may be two switches l9; as shown in Fig; 7, with the switches arranged in parallel in the plate circuit; as shown in Fig. 7, and with the parallel circuit of each switch includi'ng' a separate resistance 2'! different from the resistance 21 in the other parallel circuit to permit of control of volume.-

ZEn' the filament circuit of the tubesbetween the A battery l6 and the filaments ofthe. tubes is a switch 28 comprising two metal plates 29 and 30 disposedtransversely of each other, as shown in Fig. 2', both-havingi-nsulated support on a wall of the compartment l5 of the chassis 2. The plate 29 is connected to the spring [8 contacting a terminal of the A battery It and the plate 3015 Wired to the filaments of the tubes. The plate 30' is of resilient material constituting a. spring with one end fixed and the other end free and slightly spaced from the plate 29, similarlyto the spacing ofthefree end of: spring 2| from the plate 20 as shown in Fig. 3 and above described. A push button 3i constructed and. mounted as the push button 22 shown in Fig. 3 and above described,- may b pressed by a finger of the. opera torto press the spring 38 into. engagement with plate 29. to close thefilament circuit of the tubes. Instead of a single switch 28 in. the filament circuit of the tubes, there may. be twoswitches 28, as shown in. Fig. 2, or three, as shown in Fig. '7, the switches all being of duplicate construction and. disposed in parallel in. the filament circuit, as shown in Fig. 7, and so arranged under the buttons that the closing of a volumereduction switch. will also. closev the filament circuit.

A metallic shield 33 in connection with the metallic chassis 2 completely houses the tubes l0 and, the connections therebetween to shield the same from stray pickup. This shield 33 extends longitudinally of the handle 5, is U-shaped in cross section, and is slidable and removably mounted on the partition member 9 of the chassis 2 by means of, inturned flange 34 on the opposite edges thereof, slidably embracing the outturned flanged edges 35 of the partition member 9, the slidable, engagement for one side being shown in enlarged detai. in Fig. 6.

The terminals 36 shown in Fig. 7 are connected in conventional manner to the microphone 4 projecting from the end of the housing I, and the sound reproducer 31 conventionally shown in Fig. '7 is disposed within the compartment 38' to the sound reproducer 3'! within the compartment 38 Leading from the is a sound conveying tube 39 provided with a head 40 having a screw threaded engagement with the metal tube ll provided at its outer end with branches 42 over which are slipped the inner ends of the rubber tubes 43, engaging at their outer ends over the longitudinally curved metallic tubes 44 provided with car pieces .5. The tubes 44 adjacent their inner ends are embraced by sleeve-like members Mat the ends of a? U-shaped spring 41, for resiliently retaining the ear pieces it at the outer ends of the tubes 44 in position during use. The sound waves produced by electrical impulses through the sound reproducer 31 within the housing I are conveyed as ordinary sound waves through the tubing above described, to the ears of the physician. If desired, a physician can readily convert his present conventional stethoscope into an amplified stethoscope by simply detaching that part'of his present stethoscope that engages the chest of the patientfrom the sound tubes that lead to the ear'pieces and then slip thesev sound tubes over the branches 42 of the tubeM, as are the rubber tubes 43 abovedescribed.

As the microphonasou-nd reproducer arrdam plifier are generally of conventional design, further description of the details thereof is deemed unnecessary,.the present invention relating more particularly to a simple and compact. arrange-' ment of said parts in an. instrument adapted to be used as a stethoscope, together with manually operablemeans adapted to be readily engaged for control of the amplifier.

The terms and expressions which have been herein. employed are used as terms of. descrip tion and not of limitation, and there is no intent in the use of such terms and expressions-of excluding any equivalents of the features. shown and: described. It is recognized various modifica tions are within the scope of the invention claimed.

Having thus described my invention, what I claim as new and desire to secure by Letters Patentis:

1. In an amplified stethoscope, a housing having a microphone, an amplifieradapted for volumecontrol, a sound reproducer, and batteries disposed therein, said housing being ofelongated formation, said microphone being fixedly mounted in one end of the housing topermit placing the same against the patients body,.the opposite end of said housing constituting a handle to be grasped by a hand of the operator, manually operable means engageable exteriorly of said housing for controlling said amplifier, ear pieces, and sound conveyingtubes for connecting said sound reproducer to said ear pieces, said microphone and said means for controlling the'ampli fier both being positioned relative to said housing to. permit the operators hand which grasps the housihg to simultaneously hold the microphone against the patients body and operate the means for controlling the amplifier.

' 2. In an amplified stethoscope, a housinghaving a microphone, an amplifier adapted for volume control, a sound reproducer, and batteries disposed therein, said housing being of elongated formation, said microphone being fixedly mounted in one end of said housing, the opposite end of said housing constituting a handle, manually operable means for controlling said amplifier, said means being engageable exteriorly of saidhousing, a sound tube connected to the sound repro ducer within the housing and having branch sound tubes exteriorly of the housing, flexible tubes having their inner ends connected to said branch tubes, ear pieces, and means connecting the outer ends of said flexible tubes to said ear pieces,'said microphone and said means for controlling the amplifier both being positioned relative to said housing to permit the operators hand which grasps the housing to simultaneously hold the microphone against the patients body and operate the means for controlling the amplifier.

3. In an amplified stethoscope, a housing having a microphone, an amplifier adapted for volume control, a sound reproducer, and batteries disposed therein, said housing' being of elongated formation, said microphone being fixedly mounted in one end of the housing to be placed against a patients body, the opposite end of the housing constituting a handle to be grasped by ahand of the operator, circuits including said batteries and said amplifier, switches in said circuits, means for controlling said switches, said means being disposed adjacent the inner end of said handle and including push buttons, sound tubes having ear pieces at the outer ends thereof, and means for connecting the inner ends of said tubes to said sound reproducer, said microphone and said push buttons both being positioned relative to said housing to permit the operators hand which grasps the housing to simultaneously hold the microphone against the patients body and operate said push buttons.

4. An amplified stethoscope comprising a housing of elongated formation having a microphone, an amplifier adapted for volume control, a sound reproducer, and batteries disposed therein, a chassis for supporting said batteries and amplifier within one end portion of said housing, said end portion constituting a handle removable from said chassis to permit access to said amplifier and batteries, circuits including said batteries and amplifier, switches in said circuits, said switches being mounted on said chassis, push buttons for operating said switches and disposed adjacent the inner end of said handle, said push buttons being manually operable to operative position, and springs for operating the same to an inoperative position, said microphone and sound reproducer being disposed in the opposite end portion of said housing, a sound tube having its inner end connected to said sound reproducer and having its outer end provided with branch tubes, flexible sound tubes having their inner ends connected to said branch tubes, ear pieces, and means for connecting said ear pieces to the outer ends of said flexible tubes, said microphone and said push buttons both being positioned relative to said housing to permit the operators hand which grasps the housing to simultaneously hold the microphone against the patients body and operate said push buttons.

5. An amplified stethoscope comprising a housing of elongated formation having a microphone, an amplifier, a sound reproducer, and batteries disposed therein, a chassis for supporting said batteries and amplifier within one end portion of said housing, said end portion constituting a handle removable from said chassis to permit access to said amplifier and said batteries, circuits from said batteries to said amplifier, switches in said circuits for controlling said amplifier, said switches being mounted on said chassis, each switch including a spring for normally holding the switch open, a plurality of push buttons for operating said switches, said buttons being on the inner end of said handle and projecting through a wall thereof to be engaged exterioi'ly of the handle, said push buttons being manually operable inwardly, springs carried by the handle for operating the buttons outwardly, ear pieces, and sound tubes for connecting said 5 car pieces to said sound reproducer, said microphone and said push buttons both being positioned relative to said housing to permit the operators hand which grasps the housing to simul taneously hold the microphone against the patients body and operate said push buttons.

6. An amplified stethoscope comprising a housphone and said means for controlling the amplifier both being positioned relative to said housing to permit the operators hand which grasps the housing to simultaneously hold the microphone against the patients body and operate the means for controlling the amplifier.

'7. An amplified stethoscope comprising a housing of elongated formation having a microphone, an amplifier, a sound reproducer, and batteries disposed therein, a chassis for supporting said batteries and amplifier within one end portion of said housing, said end portion constituting a handle removably mounted on said chassis to permit access to said amplifier and batteries, and a plurality of push buttons for controlling said amplifier and disposed adjacent the inner end of said handle, said microphone and said push buttons both being positioned relative to said housing to permit the operators hand which grasps the housing to simultaneously hold the microphone against the patients body and operate said push buttons.

8. An amplified stethoscope comprising a microphone adapted to be placed against a patients body, an amplifier, a sound reproducer, supporting means for said microphone adapted to be grasped by a hand of an operator, and control means for said amplifier mounted on said supporting means, said control means being manually moved into an operative control position,

and a spring for moving the same to an inoperative position, said microphone and said amplifier control means both being positioned on said supporting means to permit the operators hand which grasps said supporting means to simultaneously hold the microphone against the patients body and operate the amplifier control means.

9. An amplified stethoscope comprising a microphone adapted to be placed against a patients body, an amplifier, a sound reproducer, supporting means for said microphone adapted to be grasped by a hand of an operator, and control means for said amplifier carried by said supporting means, said control means including a plurality of push buttons each manually operable to an operative position and a spring for moving each push button to an inoperative position, said microphone and said push buttons being positioned on said supporting means to permit the operators hand which grasps the supporting means to simultaneously hold the microphone against the patients body and operate said push buttons.

jacent the inner end of said handle, said micro- 10. In an amplified stethoscope, a housing having a microphone, an amplifier,v and a sound re.- producer disposedthereim said housing beingof elongated formation, said microphone being, disposed in one. end of said housing to be. placed against the patients body,. the opposite end. of.

said housing constituting a handle to be grasped by the hand of an operatoniand manually. operable means to be engaged exteriorly of said housing for controlling said amplifier, said microphone and said means for controlling the amplifier both being positioned relative to said housing topermit the operators handwhich grasps the housing to simultaneously hold the. microphone against the patients body andoperate the. means for controlling the amplifier.

11. In an amplified stethoscope; a microphone, an amplifier,,a sound reproducer, andsupporting means for said microphoneadapted to begrasped by a hand of an operator for placing said microphone against the body of. a patient, and man:-

REFERENCES CITED The following references are of record in th file of this patent: 15 UNITED STATES PATENTS Number Name Date 2,385,221, Minsky Sept. 18; 1945 2,001,537 Mason May 14; 1935 2,058,796.. Hogle Oct. 27-, 1936 2Q 2,159,533

ual-ly operable-means carried by said supporting;

* mit the operators hand which grasps said supporting means to simultaneously hold the microphone against the patients body and operate the amplifier control means.

MERLE F. TI-IIBOS.

Rayment May 23,1939 

